Subsea technology involves fully submerged ocean equipment, operations, or applications, especially when some distance offshore, in deep ocean waters, or on the seabed. The term ''subsea'' is frequently used in connection with

oceanography Oceanography (), also known as oceanology, sea science, ocean science, and marine science, is the scientific study of the ocean, including its physics, chemistry, biology, and geology. It is an Earth science, which covers a wide range of to ...

ocean exploration Ocean exploration is a part of oceanography describing the exploration of ocean surfaces. Notable explorations were undertaken by the Greeks, the Phoenicians, the Romans, the Polynesians, Phytheas, the Vikings, Arabs and the Portuguese. Scientif ...

, remotely operated vehicle (ROVs)

autonomous underwater vehicle An autonomous underwater vehicle (AUV) is a robot that travels underwater without requiring continuous input from an operator. AUVs constitute part of a larger group of undersea systems known as unmanned underwater vehicles, a classification tha ...

s (AUVs), submarine communications or power cables, seafloor mineral mining,

oil and gas A fossil fuel is a flammable carbon compound- or hydrocarbon-containing material formed naturally in the Earth's crust from the buried remains of prehistoric organisms (animals, plants or microplanktons), a process that occurs within geologi ...

, and offshore wind power.

Oil and gas

Oil and gas fields reside beneath many inland waters and offshore areas around the world, and in the oil and gas industry the term ''subsea'' relates to the exploration, drilling and development of oil and gas fields in these underwater locations. Under water oil fields and facilities are generically referred to using a ''subsea'' prefix, such as ''subsea well'', ''subsea field'', ''subsea project'', and ''subsea developments.'' Subsea oil field developments are usually split into ''Shallow water'' and ''Deepwater'' categories to distinguish between the different facilities and approaches that are needed. The term ''shallow water'' or ''shelf'' is used for very shallow water depths where bottom-founded facilities like jackup drilling rigs and fixed offshore structures can be used, and where saturation diving is feasible. ''Deepwater'' is a term often used to refer to offshore projects located in water depths greater than around , where floating drilling vessels and floating oil platforms are used, and

remotely operated underwater vehicle A remotely operated underwater vehicle (ROUV) or remotely operated vehicle (ROV) is a free-swimming submersible craft used to perform underwater observation, inspection and physical tasks such as valve operations, hydraulic functions and other g ...

s are required as crewed diving is not practical. Subsea completions can be traced back to 1943 with the Lake Erie completion at a water depth. The well had a land-type

Christmas tree A Christmas tree is a decorated tree, usually an evergreen pinophyta, conifer, such as a spruce, pine or fir, associated with the celebration of Christmas. It may also consist of an artificial tree of similar appearance. The custom was deve ...

that required diver intervention for installation, maintenance, and flow line connections.

Shell Shell may refer to: Architecture and design * Shell (structure), a thin structure ** Concrete shell, a thin shell of concrete, usually with no interior columns or exterior buttresses Science Biology * Seashell, a hard outer layer of a marine ani ...

completed its first subsea well in the

Gulf of Mexico The Gulf of Mexico () is an oceanic basin and a marginal sea of the Atlantic Ocean, mostly surrounded by the North American continent. It is bounded on the northeast, north, and northwest by the Gulf Coast of the United States; on the southw ...

in 1961.

Systems

Subsea oil production systems can range in complexity from a single satellite well with a flowline linked to a fixed platform, FPSO or an onshore installation, to several wells on a template or clustered around a manifold, and transferring to a fixed or floating facility, or directly to an onshore installation.API Recommended Practice 17A Subsea production systems can be used to develop reservoirs, or parts of reservoirs, which require drilling of the wells from more than one location. Deep water conditions, or even ultradeep water conditions, can also inherently dictate development of a field by means of a subsea production system, since traditional surface facilities such as on a steel-piled jacket, might be either technically unfeasible or uneconomical due to the water depth. The development of subsea oil and gas fields requires specialized equipment. The equipment must be reliable enough to safeguard the environment and make the exploitation of the subsea hydrocarbons economically feasible. The deployment of such equipment requires specialized and expensive vessels, which need to be equipped with diving equipment for relatively shallow equipment work (i.e. a few hundred feet water depth maximum) and robotic equipment for deeper water depths. Any requirement to repair or intervene with installed subsea equipment is thus normally very expensive. This type of expense can result in economic failure of the subsea development. Subsea technology in offshore oil and gas production is a highly specialized field of application with particular demands on engineering and simulation. Most of the new oil fields are located in deep water and are generally referred to as deepwater systems. Development of these fields sets strict requirements for verification of the various systems’ functions and their compliance with current requirements and specifications. This is because of the high costs and time involved in changing a pre-existing system due to the specialized vessels with advanced onboard equipment. A full-scale test ( System Integration Test – SIT) does not provide satisfactory verification of deepwater systems because the test, for practical reasons, cannot be performed under conditions identical to those under which the system will later operate. The oil industry has therefore adopted modern data technology as a tool for virtual testing of deepwater systems that enables detection of costly faults at an early phase of the project. By using modern simulation tools, models of deepwater systems can be set up and used to verify the system's functions, and dynamic properties, against various requirements specifications. This includes the model-based development of innovative high-tech plants and system solutions for the exploitation and production of energy resources in an environmentally friendly way as well as the analysis and evaluation of the dynamic behavior of components and systems used for the production and distribution of oil and gas. Another part is the real-time virtual test of systems for subsea production, subsea drilling, supply above sea level, seismography, subsea construction equipment, and subsea process measurement and control equipment.

Offshore wind power

The

power transmission Power transmission is the movement of energy from its place of generation to a location where it is applied to perform useful Mechanical work, work. Power (physics), Power is defined formally as units of energy per unit time. In SI units: :\text ...

infrastructure for offshore wind power utilizes a variety of subsea technologies for the installation and maintenance of submarine power transmission cables and other electrical energy equipment.Global Marine Systems on the future of offshore wind cabling
, ''Wind Energy Update'', 2009-09-10, accessed 2011-07-30. In addition, the monopile foundations of fixed-bottom wind turbines and the

anchor An anchor is a device, normally made of metal, used to secure a vessel to the bed of a body of water to prevent the craft from drifting due to wind or current. The word derives from Latin ', which itself comes from the Greek (). Anch ...

ing and cable structures of floating wind turbines are regularly inspected with a variety of shipborne subsea technology.

Underwater mining

Recent technological advancements have given rise to the use of remotely operated vehicles (ROVs) to collect

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): Mi ...

samples from prospective mine sites. Using drills and other cutting tools, the ROVs obtain samples to be analyzed for desired minerals. Once a site has been located, a mining ship or station is set up to mine the area. Seafloor mineral mining of seafloor massive sulfide deposits (so named for the sulfide molecules, not the deposit size) are a developing subsea mineral

mining industry Mining is the extraction of valuable geological materials and minerals from the surface of the Earth. Mining is required to obtain most materials that cannot be grown through agricultural processes, or feasibly created artificially in a la ...

. Nautilus Minerals Inc. had begun to establish a new industry by commercially exploring and, in the future, planned to extract copper, gold, silver and zinc in its Solwara 1 Project. The project was establishing its operations beneath the ocean surface in the

Bismarck Sea The Bismarck Sea (, ) lies in the south-western Pacific Ocean within the Papua New Guinea, Papua New Guinean exclusive economic zone. It is located north-east of the island of New Guinea and south of the Bismarck Archipelago. It has coastlines i ...

near

Papua New Guinea Papua New Guinea, officially the Independent State of Papua New Guinea, is an island country in Oceania that comprises the eastern half of the island of New Guinea and offshore islands in Melanesia, a region of the southwestern Pacific Ocean n ...

. When fully underway the operation would have been the world’s first commercial deep sea mining project. First production was expected to begin in 2017, but the company went bankrupt in 2019 after failing to secure funding for the project.

Remotely operated vehicles

Remotely Operated Vehicles (ROVs) are robotic pieces of equipment operated from afar to perform tasks on the sea floor. ROVs are available in a wide variety of function capabilities and complexities from simple "eyeball" camera devices, to multi-appendage machines that require multiple operators to operate or "fly" the equipment. Other Professional Equipments used in installation of Sub Sea Telecommunication cable are specially designed crafts, modular barges, Water Pump along with Diving support and other accessories to seamlessly conduct installation operations in Deep Sea and Near Shore end, Rivers, Lakes. There are few professional companies in the world who own, operate such equipments and carry out operations worldwide on turnkey basis.

Energy harvesting and production

Subsea energy technologies are the subject of investigation using a number of technical strategies, none of which have yet been commercialized to become viable products or new energy industries. Energy sources under investigation include utility scale power production from ocean currents, such as the rapid currents found in the waters between the Florida Straits and Cape Hatteras. Research and projects are developing to harvest energy from hydrothermal vents to provide power for subsea ocean research instruments, developing autonomous vehicle recharge technologies, seabed sensor systems, and environmental research applications. Other investigations include harvesting energy from differences in temperature that occur with varied ocean depth, and microbial fuel cells that produce energy from organisms in ocean seafloor sediments. Current methods for providing power for electric applications on offshore seabeds are limited to the use of batteries, power provided from generators on ships or platforms with fossil fuel generators, or for lower power requirements, wind, solar, or wave energy harvesting buoys.

Organizations

A number of professional societies and trade bodies are involved with the subsea industry around the world. Such groups include
Subsea Engineering SocietySociety for Underwater TechnologySubsea Project AwardsGlobal Underwater Hub
* Subsea Valley The largest subsea technology business cluster.
Society of Petroleum Engineers
*

American Petroleum Institute The American Petroleum Institute (API) is the largest U.S. trade association for the oil and natural gas industry. It claims to represent nearly 600 corporations involved in extraction of petroleum, production, oil refinery, refinement, pipeline ...

(API) *

American Society of Mechanical Engineers The American Society of Mechanical Engineers (ASME) is an American professional association that, in its own words, "promotes the art, science, and practice of multidisciplinary engineering and allied sciences around the globe" via "continuing edu ...

(ASME) * National Association of Corrosion Engineers (NACE) * International Marine Contractors Association (IMCA) Government agencies administer regulations in their territorial waters around the world. Examples of such government agencies are the Minerals Management Service (MMS, US), Norwegian Petroleum Directorate (NPD, Norway), and Health & Safety Executive (HSE, UK). The MMS administers the mineral resources in the US (using

Code of Federal Regulations In the law of the United States, the ''Code of Federal Regulations'' (''CFR'') is the codification of the general and permanent regulatory law, regulations promulgated by the executive departments and agencies of the federal government of the ...

(CFR)) and provides management of all the US subsea mineral and

renewable energy Renewable energy (also called green energy) is energy made from renewable resource, renewable natural resources that are replenished on a human lifetime, human timescale. The most widely used renewable energy types are solar energy, wind pow ...

resources.

References

{{reflist Underwater work Technology by type